1. Field of the Invention
The present invention is directed to denture adhesives or stabilizers, and particularly to an improved denture adhesive composition.
2. Description of the Prior Art
Traditionally, dentures within the mouth were secured by using adherent powders prepared from natural gum materials such as karaya, acacia or tragacanth gum. These materials have the property of swelling to many times their original volume upon the addition of water to form a gelatinous or mucilaginous mass. Cream forms of the adherent, prepared from finely ground particles of the gums, were also available and used instead of the powder composition.
Over the years, there have been numerous improvements over the above-described simple denture adhesive formulations. U.S. Pat. No. 2,978,812 discloses a denture fixative composition which includes an ethylene oxide polymer having a molecular weight between 50,000 and 5,000,000 in an amount preferably comprising at least 50% of the active fixative material. GB Patent No. 1,444,485 discloses a fixing agent comprising a solution of 4 to 44 wt. % of a polyvinyl pyrrolidone ("PVP"). U.S. Pat. No. 3,003,988 describes the use of mixed salts of more than 40 wt. % of a water-insoluble water-sensitized polymeric material consisting essentially of lower alkyl vinyl ether maleic anhydride polymers. U.S. Pat. No. 5,001,170 discloses a substantially anhydrous mixture of about 20 40 wt. % methyl vinyl ether maleic acid copolymer, 20-40 wt. % of PVP, and 20-40 wt. % of ethylene oxide polymer.
The use of ethylene oxide polymer, or polyethylene oxide ("PEO"), has declined recently, being supplanted by metal crosslinked polymers which exhibit greater strength. Recent improvements include the use of a lower alkyl vinyl ether maleic acid, anhydride, or salt polymer or mixtures thereof and one or more metallic salts selected from the group consisting of calcium, magnesium, strontium, sodium, potassium, zirconium, and zinc or mixtures thereof. U.S. Pat. No. 5,830,933 discloses a denture adhesive composition with about 15-55 wt. % of a salt of a copolymer of maleic acid or anhydride.
Applicants have found that by simply complexing PEO chains to PVP molecules surprisingly improve the cohesive strength of PEO, yielding denture adhesive formulations comparable to formulations based on salts of polymaleic acid methyl vinyl ether in sensory tests as well as cohesive strength, without the need for metal crosslinked polymer systems.